Control valve adapted for pressure differential motor use



1964 G. T RANDOL 3,145,625

E DIFFERENTIAL MOTOR USE CONTROL VALVE ADAPTED FOR PRESSUR 4Sheets-Sheet l Original Filed Sept. 2

Q UNM m 3 mm 5 MN Nm Aug. 25, 1964 G. T. RANDOL I 3,145,625

CONTROL VALVE ADAFTED FOR PRESSURE DIFFERENTIAL MOTOR USE Original FiledSept. 2, 1958 4 Sheets-Sh t 2 AF D /80 a A 4 4 4 FIG. 2. 4

5 I67 I57 I a 64 I 5- 271 I 7; as d [6 97 8 A707 09 l I 3778 l n. pg712/ 10a 7, I I05 5 "2oz ""79a==-- ,g 9 I Aug. 25, 1964 G. T. RANDOL3,145,625

CONTROL VALVE ADAFTED FOR PRESSURE DIFFERENTIAL MOTOR USE 4 Sheets-Sheet3 Original Filed Sept. 2, 1958 FIG.3.

Aug. 25, 1964 G. T. RANDOL CONTROL VALVE ADAFTED FOR PRESSUREDIFFERENTIAL MOTOR USE Original Filed Sept. 2, 1958 4 Sheets-Sheet 4 4I22 I57 B A 15510 207209 m8 FIG. 7.

Imntoi United States Patent Oflice 3,145,625 Patented Aug. 25, 1964 12Claims. c1. 91-374 This application is a division of my copendingapplication Serial No. 758,405, filed September 2, 1958, abandoned infavor of continuing application Serial No. 122,037, filed July 5, 1961,now issued to Patent No. 3,072,106, dated January 8, 1963.

In my original application referred to, I have disclosed avacuum-operated booster motor having a casing with a power member orwall movable therein, and which is adapted to operate in part thehydraulic master cylinder of hydraulic brake systems on automotivevehicles and the like. Activation and inactivation of said power memberbeing under control of novel and improved follow-up valve mechanismcomprising at least two principal cooperating elements which arerelatively displaceable from normal off position wherein the motor isinactivated, to operating on position wherein the motor is activated,under influence of an operator-operated member opposed by resistance(work load) reacting on said power member, said valve mechanism alsoincluding a separate auxiliary air control valve radially offset fromthe axis thereof and controlled conjointly by said operator member tocooperate with said off position to expedite incursion of air into thevacuum-power chamber of said motor for rapid return of the power memberto its normally released position wherein the brakes are off. There arecertain features of construction and operation which relate particularlyto the valve mechanism per se, thus rendering such mechanism applicablefor controlling motors of the type under consideration in operativeassociation with systems and/ or devices other than those whichcharacterize vehicular brake systems. These features of the valvemechanism per se form the subject-matter of the present application.

The present invention has for a primary object, the provision of new andimproved follow-up valve mechanism operable from said operator member tocontrol operative energization of said motor, said valve mechanismcomprising at least two principal cooperating elements, one of whichslidably interfits the other and adapted to operatively support thevalve mechanism as a unit on the motor casing independently of saidpower member, and an auxiliary air control valve incorporated in thepower member in radially oflset disposition with respect to the axis ofthe interfitting elements aforesaid for control by said operator memberin synchronism with the interfitting elements whereby incursion of airinto the-motor power chamber is expedited to accelerate return movementof the power member to normal position.

An object related to the above primary object is to provide novelcontrol valve mechanism for servomotors and the like, wherein saidinterfitting elements are coaxially disposed with respect to each otherand to said power member, and which are adapted to selectively balancepressures on opposite sides of the power member for power-inactivationof said servomotor, and establish differential pressures on oppositesides of the power member for power-activation of said servomotor, saidvalve mechanism including an auxiliary valve incorporated in the powermember in radially ofiset disposition with respect to the axis of thelatter member, for cooperating with the off disposition of saidinterfitting elements to effect said balanced pressures for the purpose.

A more specific object of the invention is to provide new and improvedfollow-up valve mechanism comprising a pair of telescopically-relatedcylindrical elements for controlling a source of sub-atmospheric(negative) pressure, and a poppet-type element for controllingatmospheric pressure, said pair of elements and the poppet element beingselectively controllable by said operator member to establish equivalentpressures within the motor casing on opposite sides of the power memberfor powerinactivation of the motor and to establish differentialpressures therein on opposite sides of the power member forpower-activation of said motor, respectively.

An object related to the above specific object is the provision of novelmechanical interconnecting means between one of the pair of elements andsaid poppet element to enable conjoint movement thereof to open saidpoppet element thereby interconnecting opposite sides of said powermember to balance pressures thereagainst, said poppet element includinga normally preloaded spring biasing the same to closed position insynchronism with opening of said pair of elements to on position toproduce differential pressures on opposite sides of the power member.

Another object related to the two specific objects above is to provide amechanical link between said operatoroperated member and one of saidpair of elements to control said pair of elements and the poppetelement, and whereby direct actuation of the power member may beeffected in the event of power inadequacy or failure notwithstanding thesaid pair of elements and operatively associated poppet element are inactuated dispositions corresponding to power-activation of the powermember.

Another object of the invention is to provide said pair of coaxialelements with novel spring means to separate them to their normaldisposition wherein the booster motor is inactivated, said meansincluding manually adjustable mechanism to selectively establish thedesired normally preloaded condition thereof.

Another object of the invention is to utilize in a novel manner aflexible conduit to interconnect the power member with the side of thepair of elements opposite to that connected with another flexibleconduit leading to the source of pressure.

The invention, therefore, provides novel auxiliary or vacuum reliefvalve means operably incorporated in the power member for venting thevacuum-power chamber of a brake booster motor to atmosphere via theatmospheric chamber in said motor in cooperation with a restrictedair-vacuum opening in the main control valve means comprising said twointerfitting coaxial elements to enable quick release of the powermember irrespective of the mode of brake-pedal manipulation so thatbrake release keeps pace with the rate of withdrawal of foot pressurefrom the pedal, said restriction of the air-vacuum opening providing theadvantage of effecting gradual excursion of air from the vacuum-powerchamber for smoothly controlling energization of the booster motor whilesaid restriction inherently retards incursion of air into saidvacuum-power chamber with corresponding slow release of the power memberwhen taking the brakes off despite quick removal of foot pressure fromthe brake-pedal. Therefore, the relief valve means serve the importantand useful purpose of enabling brake release in synchronism with therate of brake-pedal return movement according $0 the rapidity with whichpressure is removed from the atter.

A further optional feature provided by the present invention is a novelmechanical connection between the inner of the pair of valve elementsand the associated power member controlled thereby, wherein theconnected elea ments and power member have axial movement as a unit withlimited radial floating movement therebetween to enemas prevent bindingand/ or Wear on the operating parts which could result to an excessivedegree should the connection between the power member and inner valveelement not provide for radial deflections therebetween. Thus, thisconnection eliminates need for critical tolerances to maintain coaxialexactness between the power member and valve mechanism therefor sincethese two components are capable of limited lateral displacementrelative to each other without hindering their free axial movement as aunit.

With these and'other objects and advantages in view, the inventionconsists of the new and novel combinations, constructions andarrangements of parts as hereinafter more fully described, setforth inthe claims appended hereto, and disclosed in the accompanying drawingsforming part hereof, wherein:

FIGURE 1 is a longitudinal vertical section of a brake booster motorincorporating control valve mechanism constructed in accordance with thepresent invention, said motor being exemplarily illustrated in operativeassociation with the master cylinder in a hydraulic brake systemconventionally employed on automotive vehicles or the like, and whereinsaid valve mechanism is in its closed (off) disposition;

FIGURE 2 is a fragmentary view of FIGURE 1 on an enlarged scale of thevalve mechanism per se with certain parts shown in elevation;

FIGURE 3 is a transverse sectional view taken on a reduced scale alongthe line 3-3 of FIGURE 2, and showing details of the auxiliary vacuumrelief valve;

FIGURE 4 is another transverse sectional view taken on a reduced scalealong the line 4-4 of FIGURE 2, and showing further details of the novelvalve structure and associated flexible conduit connections leading tothe exterior of the motor casing and to the vacuum-power chamber via thepower member;

FIGURE 5 is a sectional view similar to FIGURE 2 on substantially thesame scale showing the parts in their respective operated positionscorresponding to valve open (on) position to inaugurate operativeenergization of the booster motor;

FIGURE 6 is a fragmentary view of FIGURE 2 showing the vacuum reliefvalve on an enlarged scale for clarity of detail;

FIGURE 7 is a fragmentary view of FIGURE 5 showing the vacuum reliefvalve on an enlarged scale for clarity of detail;

FIGURE 8 illustrates a modified form of the control valve mechanismwherein the inner valve piston is mechanically connected to the powermember for axial movement as a unit, said coupling accommodatingrelative radial displacement between these two components; and

FIGURE 9 is a transverse sectional view of FIGURE 8 taken along the line9-9 thereof to show further details of the mechanical couplingarrangement between the valve piston and power member.

Referring now to the drawings wherein like reference charactersdesignate like and corresponding parts through out the several views,except in a modified embodiment of the invention wherein similar partsare distinguished, however, by the addition of the letter a to each, theillustrative embodiments are disclosed in operative association with apressure differential operated booster motor disclosed herein as avacuum-operated motor or power cylinder designated as a whole VM of theair-suspended type, and having a cylindrical casing formed with twocup-shaped shells 4t), 41 connected as by bolts 53 projecting throughcomplemental outturned flanges which terminate the open ends of theshells, the opposite ends thereof being closed by integral walls 11, 34respectively as shown, said casing being fitted with a power memberassembly or wall designated as a whole PA movable therein from anormally released position to operate in part the master cylinder MC inthe conventional hydraulic brake system on automotive vehicles or thelike, said power assembly dividing the interior of said casing into avariable pressure (vacuum) chamber 45 and a constant pressure(atmospheric) chamber 46.

The power assembly PA comprises a pair of circular plates 47, 4S and aring-like flexible diaphragm generally designated D. The inner marginalportion of the diaphragm being clamped between the peripheral marginalportions of said plates, and the outer marginal portion of the diaphragmbeing anchored'in airtight sealed relationship between the casingflanges as shown. The central portions of the assembled plates 47, 48are reinforced by circular thrust plates 55, 56 respectively, and acircular spacer plate 58 disposed in a coaxial opening 49 in the plate47 between plates 55 and 48. The aforesaid plates and the diaphragm areassembled as a unit by suitable fasteners projecting therethrough suchas illustrated at 57. A central circular opening 63 is provided in thethrust plate 55 for an important purpose to become apparent.

A cylindrical pilot element or stem provided with an annular flange 71is coaxially fixed to the forward side of the thrust plate 55 forslidably supporting one end of a thrust-transmitting member or plunger77 in normally engaged relationship with said stem, the other end ofsaid plunger being adapted to engage the master cylinder piston toactuate the same as shown. Slidably mounted on the flange '71- is acentrally apertured cup-shaped spring seat member which is mechanicallyinterconnected with one element of the novel control valve mechanismhereinafter to be described in detail, for movement as a unit by aplurality of actuating pins 64 radially offset from the axis of thepower diaphragm assembly PA and operably projecting therethrough insealed relation. A normally preloaded compression spring 102 encircles aportion of the plunger '77 and reacts between the forward end wall 11 ofthe motor casing and said spring seat member to urge the latter, thepower assembly PA and said one element of the valve mechanism in areleasing direction only to inactivate said booster motor.

Incorporated between the one end of the plunger 77, and the peripheralflange 101 of the spring seat member 5 and the stem flange '71, is anovel reaction device generally designated RD, said device comprising aplurality of radially disposed levers which levers may be integrated toproduce a circular disc, or the latter perforated to form individuallevers as shown in the parent application, characterized by resiliencyor optionally by rigidity, said levers being adapted to transmitprogressively increasing reaction from the master cylinder MC when thelatter is operating to pressurize'the fluid therein, to the operatormember in cooperation with the biasing eifect of the spring 102 there byproviding the operator with physical awareness of the degree of brakingpressure in effect.

The follow-up control valve mechanism generally designated CV is of newand improved construction and operation and comprises: two principalcomponents; namely, a main air-vacuum valve CV for controlling incursionand excursion of air into and from the vacuumpower chamber 45, and anauxiliary air valve AV operatively correlated with the air controlfunction of said main control valve to balance pressures in said motorchambers 45, 46 and thereby accelerate the releasing movement of thebooster motor VM and therefore the vehicle brakes in accordance with therapidity with which foot pressure is removed from the operator-operatedmember disclosed herein as a brake-pedal designated P of thesuspended-type, and which comprises a pedal arm 35 pivotally suspendedfrom its upper end on the vehicle at 36, and the lower end of said armterminating as a foot pad 37 whereby the operator may exert effort onthe pedal P to operate the same. A push-rod PR is pivotally connected at38 to an intermediate point on the pedal arm to act on the said oneelement of the main control valve CV to control the same in a novelmanner.

The main control valve CV is similar in construction and operation tothat disclosed in my prior copending application Serial No. 684,946,filed September 19, 1957, now Patent No. 3,101,032, and which comprises:an outer and an inner telescopically-related element 105, 106 which aredisclosed herein as a cylindrical valve sleeve and a valve pistonrespectively. The valve sleeve 105 is provided with a longitudinal bore107 extending from its inner end to substantially a medial point thereinand a re duced coaxial bore 108 extending from the other end to suchdepth as to provide a thrust wall 109 between said bores. Spaced fromthe inner end of the valve sleeve is a vacuum-slot 110 through the wallthereof communicating with the bore 107, and longitudinally spacedrearwardly from said slot 110 is a fluid-control slot 111 through thewall of the valve sleeve in a diametrically disposed relationship andcommunicating with the said bore 107. An internal annular groove 114 isprovided in the surface of the bore 107 adjacent the inner end of thevalve sleeve.

The valve piston 106 is a spool-type element comprising a pair oflongitudinally spaced annular lands 116, 117 which define a ring-likevacuum chamber 118 therebetween in continuous communication with thevacuumslot 110, the outer opposite ends of said lands terminate inreduced diameter cylindrical extensions 119, 120 respectively. Thecylindrical surface of the extension 120 is threaded and the free end ofthe extension 119 is loosely piloted in the opening 68 in plate 56aforesaid to maintain substantially coaxial relationship between thecontrol valve mechanism and the movable power assembly PA, and also toenable the end of extension 119 to engage the confronting surface areaon the plate 48, and thereby move as a unit to produce the usualfollow-up action requisite for operation of the main control valve meansCV provided by the relative movement therein to effect opening andclosing of the control-slot 111. The valve land 117 is spaced from thethrust wall 109 to provide an atmospheric chamber 121 therebetweenselectively connectible to the control-slot 111, said land being termeda working land because it is operative to selectively connect thecontrol-slot 111 to the vacuum valve chamber 118 and to the atmosphericchamber 121, said vacuum valve chamber being subject to vacuum (negativepressure) at all times when the engine is running via the vacuum-slot110, such sub-atmospheric conditions being generated, for example, inthe engine inlet-manifold (not shown) as a vacuum source. Operablydisposed in the valve chamber 121 is a normally preloaded compressionspring 122 having one end bearing on the thrust wall 109 and the otherend piloted on the reduced threaded extension 120 to react on theconfronting face of a preferably hex-type nut 123 threaded onto saidextension to normally engage the end of the valve land 117, said nutbeing capable of manual adjustment along the extension to in crease ordecrease the tension on spring 122 and thereby vary the degree ofshoe-to-drum contact during the initiatory brake-applying stroke. Thisspring is effective to separate the valve piston and sleeve andaccommodate their movement toward each other within the limits of therelative operating movement shown at 125 normally obtaining between theinner end of the valve sleeve 105 and confronting surface area on thethrust plate 56 to enable the valve elements to move relatively to eachother to control operative energization of the power assembly PA. Asplit retainer ring 126 engages the groove 114 for engagement by theperipheral outer face portion of the valve land 116 to establish thenormal separated status of the main valve elements under influence ofthe spring 122 as shown in FIGURE 2, and wherein the relative operatingdisposition of the valve sleeve is shown with respect to the thrustplate 56 in readiness for a valve operating cycle as will appear.

Encircling the forward portion of the valve sleeve 105 is a valvehousing generally designated VH and comprising a pair of interchangeablesemicircular segments 128, 129 clamped around this portion in air-tightsealed relation by a pair of hex cap screws 130 oppositely projectingthrough holes 131 in a pair of laterally extending flanges or cars 132which terminate opposed arcuate portions of said segments, into threadedholes 133 through complemental lateral flanges or ears 134 whichterminate the other opposed arcuate portions of said segments to thustightly clamp the two halves 128, 129 of the valve housing VH on thevalve sleeve to provide a unitary assembly thereof. Formed in the innercurved surface of each of the segments 128, 129 is a rectangular-shapedarcuate cavity 135, with cavity in the upper segment 128 havingcontinuous communication with the cross-slot 111 and the other segment129 having continuous communication with the vacuum-slot via the cavity135 thereof. Aligned with the cavity in the upper segment 128 is arectangular-shaped upstanding embossment or boss 136 integral with thecircular wall of said segment, and there is a similar embossment or bossdepending from the circular wall of the lower segment 129. Each of saidembossments is provided with a vertical hollow or passageway 138 whichcommunicates with the cavities aforesaid, and a substantially horizontalpassageway 139 continuously communicates with each of said hollows. Arigid tubular fitting 141 is pressed at one end into each of thepassageways 139 to provide a vacuum inlet into the interior of the maincontrol valve CV, and an air-vacuum connection from said valverespectively as will appear. The inner ends 142 of the semicircularwalls of the segments 128, 129 in assembled relation terminate flushwith the inner end of the valve sleeve 105 to provide a circular workingface 143 which continuously engages the ends of the pins 64 projectingthrough the movable power assembly PA whereby movement of the valvesleeve actuates said pins which in turn simultaneously move the springseat member 95 disposed adjacent the opposite side of the power assemblyPA best demonstrated in FIGURE 2. The aforesaid working face ispredeterminately spaced normally from the confronting face area on theplate 56 to establish the relative operating movement of the maincontrol valve means CV whereby movement of the valve sleeve 105 to openthe control valve means CV actuates the pins 64 relatively to thediaphragm plates 55, 56 to move the spring seat 95 forwardly away fromthe plate 55 to additionally compress the spring 102 and thereby produceincreasing resistance to movement of the valve sleeve 105, whichresistance is progressively induced in accordance with the distance themovable wall PA is moved as a measure of the pressure being exerted bysaid movable wall on the brake fluid in the hydraulic brake system (notshown). It should be importantly noted here that during energization ofthe vacuum-motor VM, the spring 102 reacts only on the spring seat 95and valve sleeve 105 which prevents power-loss that would result shouldthe movable wall PA be required to overcome the force of this spring asis common practice in prior art devices.

Intermediately spaced With respect to the cavities in the aforesaidsegments 128, 129 and the rear ends of the circular walls thereof, is asemicircular internal groove 145 which in the assembled status of thehousing segments produces an internal annular groove 146 which receivesthe outer half-diameter in cross section of a split round wire retainerring 147, and the inner half-diameter thereof engages a circularlyaligned external annular groove 148 in the outer cylindrical surface ofthe valve sleeve 105 to lock the valve housing segments against relativeaxial displacement with respect to said sleeve.

Each of the segments 128, 129 is provided with an indentation or notch150 in the rear end of the circular walls thereof and diametricallydisposed in their assembled status on the valve sleeve 105. Thesenotches register with correspondingly disposed ports 151 through thewall of the valve sleeve whereby the atmospheric valve chamber 121communicates continuously with the power cylinder atmospheric chamber46.

The power cylinder end wall 34 is provided with a circular opening 154coaxial with the openings in the forward end wall 11 and associatedplates aforesaid, said opening 154 terminates in an outturned circularflange 155 which is radially closed inwardly into an external annulargroove 156 formed in the outer cylindrical surface of a hearing orsupport collar 157 to make the collar fast on the end wall 34. Theinterior of the collar is provided with an inner counterbore 158 incoaxial disposition with respect to a longitudinal bore 159 to providean annular shoulder 160 therebetween, the bore 159 serving as a bearingsupport for the rearwardly projecting portion of the valve sleeve 105exterior of the valve housing VH best demonstrated in FIGURE 2. Shoulder160 is engageable by the rear ends of the valve housing segments 128,129

aforesaid to establish the main control valve mechanism CV in itsnormally released position. Another external annular groove 161 isprovided on the collar 157 rearwardly spaced from the groove 156 forreceiving the annular forward end retaining bead 162 of a conventionalflexible dust boot B.

The free end 165 of the push rod PR projects through a reduced diameterbead 166 terminating the opposite end of said boot B intothe bore 108 inthe valve sleeve 105 to engage the thrust wall 109 whereby movement ofthe pedal P is transmitted via the push rod PR to actuate the valvesleeve 105 relatively to the valve piston 106, and as a unit with thelatter upon the relative operating movement of the main control valvemechanism CV being fully taken up as a consequence of the working face143 engaging the plate 56 to provide a straight through application ofoperator input effort on the movable power assembly PA to assist themaximum output effort of the latter to apply the brakes.

A rigid vacuum-inlet tube 170 projects through the cylindrical wall ofcasing 41 at 171 (see FIGURE 1), the inner projecting portion 172receives the end of substantially a convolution of flexible conduit 173and the other end of said conduit is attached to the tube 14-1 in thelower valve housing segment 129 whereby vacuum inlet to the arcuatecavity 135 thereof and relative movement of the control valve sleeve 105with respect to the movable wall PA are provided. One end of anotherflexible conduit 175 is connected to the free end of an elbow-type tube176 having its other end secured to and projecting through the plates55, 56 in continuous communication with the power chamber 45 aforesaidand, the other end of the last-mentioned conduit being connected to theupper tube 141 whereby the cavity 135 in the upper housing segment 128is connected to said power chamber and relative movement between themovable power assembly PA and control valve sleeve 105 also providedthereby. That portion of the tube 170 which projects to the exterior ofthe casing 41 receives one end of a third flexible conduit 178 and theother end of this latter conduit is connected, for example, to theinterior of the engine-inlet manifold (not shown), thereby completingthe vacuum line connection to the main control valve mechanism CV.

An air filter device of conventional construction is provided at AF (seeFIGURE 1) and which is pressfitted or otherwise secured in an opening180 through the cylindrical wall of the power cylinder casing 41 forventing the power cylinder chamber 45 to atmosphere via chamber 46, andfor filtering out any foreign particles, moisture, etc., from enteringsaid chambers with consequent involvement of the working parts withinthe booster motor VM. This filter device further serves to silenceingress of air when the vacuum-motor VM is being operated to releasedposition in response to removing pressure from the pedal P and whereinthe motor vehicle brakes are taken off as is understood.

The auxiliary or vacuum relief control valve AV comprises a longitudinalcircular passageway 195 radially offset from the axis of the maincontrol valve CV, and which extends through the plates 55, 58, 56 inthat order S to normally place the power cylinder chambers 45, 46 incommunication with each other when open, thereby balancing pressures onopposite sides of the power member PA. The end of this passageway on theplate 56 terminates in'an annular preferably flared valve seat 196 asshown. A poppet-type valve element 197 is movably disposed in thepassageway and provided with a head 198 having a complemental face 199for engaging the said valve seat to close said passageway. Projectingfrom the head through the passageway is a stem 200-having a plurality ofelongated radially disposed fins 201 of substantially the same overalldiameter as the passageway to slidably support the valve element inengaging alignment with its valve seat aforesaid, said fins providinglongitudinal spaces 202 therebetween to enable air flow through thepassageway when open. The stem operably engages the confronting portionof the back of the spring seat member in normal disposition as shownin-FIG- URE 2 to move the head of the valve element 157 away from itscooperating seat and thus connect the chambers 45, 46 so that pressureson opposite sides of the movable power member PA are balanced. Thelength of the stem 200 is such that upon movement of the spring seatmember 95 away from the thrust plate 55, under influence of the pedal P,that the poppet valve engages the seat 196 to isolate the chambers 45,46 from each other thereby conditioning the movable power member PA tobe subject to differential pressures on opposite sides thereof inducedby opening the main control valve CV after the poppet valve 197 has beenseated. It should be noted in this connection that the valve sleeve andspring seat member 95 move simultaneously and the timing of the openingof the control-slot 111 to evacuate the power chamber 45 of air is suchthat this latter operation transpires as or after the poppet valvecloses in the manner explained above, otherwise, air in the powerchamber 45 could not be evacuated to create such differential pressuresunder control of the main control valve CV since chamber 45 would beconnected to atmosphere via chamber 46. Stated differently, the poppetvalve must be closed before the main control valve CV can be effective,even though open, to energize the vacuummotor VM. This poppet valve maybe termed a vacuurn-relief or auxiliary valve since its purpose is toplace both chambers of the power cylinder VM in communication withatmosphere upon removal of foot pressure from the pedal P at any appliedposition thereof, to

enable the return springs aforesaid and pressure on the brake fluid toeffect quick return of the mechanism to brake off position irrespectiveof the rate of withdrawal of the foot from the pedal whereby theoperating parts associated with the pedal keep pace with it toward fullyreleased position. In this way, a slowed brake release is prevented thusmaking it possible to apply and release the brakes as rapidly asconditions require. Of course, the control-slot 111 could be made widerand deeper in the valve sleeve 105 with the valve working land 117proportionately widened to accommodate a more rapid ingress of air intothe power chamber 45 when taking the brakes off but such would act adversely to a smooth sensitized control of the booster motor VM inrelation to the shortest possible pedal travel requirement to effectoperation of the main control valve CV. Accordingly, the poppet valveserves as an auxiliary air inlet to the power chamber 45 in cooperationwith the off position of the main control valve CV so that release ofthe vehicle brakes occurs in synchronisrn with the rate of removal offoot pressure from the pedal P; but if the main control valve CV isslowly released, ingress of air via the control-slot 111 into the powerchamber 45 enables the retraction of the operating parts simultaneouslywith pressure removed from the pedal as is understood. In either case,however, venting of both motor chambers 45, 46 to atmosphere by thepoppet valve at full release of the pedal pressure assures that 9 theoperating parts are fully established in their respective releasedpositions wherein the master cylinder compensating port is fullyuncovered for the fluid to properly adjust in the hydraulic system.Partial evacuation of the power chamber 45 tends to draw the poppetvalve head 198 toward its seat by the air pressure effective on theopposite side of the head and thus seal off the chamber 45 from thechamber 46, however, a normally preten sioned fiat leaf spring 203 isprovided with one end anchored as by a drive pin 204 on the plate 56 andthe other end overlying the valve head to react thereagainst to insureseating of the head when the stem 209 is released by movement of thespring seat member 95 away from the thrust plate 55 as shown in FIGURE 6where slight clearance obtains between the end of the stem and verticalwall of the spring seat member 95. Closed condition of the relief valvemust coincide with the lapped position of the working land 117 andcontrol-slot 111 to enable holding the brakes on.

The support collar 157 is further provided with a radial passageway'207which is flared at its outer end, and the inner end of which intersectsan internal annular channel 208 formed in the bore 159. An oil saturatedring-type wick 209 is carried in this channel in encircling relationwith respect to the exposed exterior cylindrical surface of the valvesleeve 105, to provide lubrication for this surface and the surface ofthe bore 159. A fiat 210 having a shoulder 211 is provided in the outersurface of the valve sleeve 1115 which communicates with the wick 209 inthe normally released disposition of the control valve mechanism CVshown in FIGURE 2, said flat having continuous communication with theupper air port 151 whereby ingress of air through this port induces thelubricant suspended in the wick to move toward said air port and thenceinto the interior of the sleeve to lubricate the valve piston 106. Theaforesaid shoulder which terminates the rear end of the flat 210 tendsto wipe the lubricant from the wick during sliding movement of thesleeve 105 relative to the collar 157 which wiping action cooperateswith the air flow into the interior of the valve sleeve 105 to place atintervals small quantities of lubricant near the port 151 so that it maybe drawn into the interior of the sleeve. In this manner an efiicientlubricating system is provided for the working parts aforesaid by simplyintroducing periodically a small quantity of oil as by the spout of anoil can engaging the flared end of the passageway 207, to maintain thewick saturated. Over lubrication is prevented by the control-slot 111and bottom air port 151 which drain off excess oil, the port 151conveying such excess to the atmospheric chamber 46 of the vacuum-motorVM, and any excess oil reaching the cavity in the lower valve housingvia control-slot 111 when the main control valve CV is disposed as shownin FIGURE 2, would be drawn into the vacuum valve chamber 118 when themotor is energized with consequent lubrication of both of the valvelands, and any excess lubricant in the vacuum chamber would ultimatelyreach the engine inlet-manifold (not shown) under influence of vacuumand dissipated in the combustion chambers of the engine as isunderstood.

Operation The operation of my improved fllOW-up control valve mechanismCV will be apparent from the foregoing description but may be summarizedas follows:

Assuming that the valve sleeve and piston 1115, 1116 respectively of themain control valve CV are in their normally released positions as shownin FIGURES 1 and 2 wherein the vacuum-power and atmospheric chambers 45,46 respectively are vented to atmosphere via air filter device AFthereby balancing pressures in said chambers for power-inactivation ofthe booster motor VM, said power chamber 45 being vented via the elbowfitting 176, conduit 175, tube 141, cavity 135 in valve segment 123,passageway 139, control-slot 111, atmospheric valve chamber 121, ports151, notches 156, atmospheric chamber 46 and the air filter AF, and, aspreviously stated, the chamber 46 is in continuous communication withthe atmosphere via the said air filter device. Also the vacuum reliefvalve AV is in open disposition as shown in FIGURES 1, 2 and 6 therebycooperating with the control-slot 111 in the main control valve CV innormally released position to unrestrictedly accommodate free flow ofair between the motor chambers 45, 46 to balance the pressure therein.Accordingly, the booster motor VM and related parts including themovable power assembly PA therein are in their respective normallyreleased positions as shown in FIGURES 1 and 2 in readiness for abrake-applying cycle.

With the engine running, sub-atmospheric (negative) pressure is producedwithin the intake-manifold (not shown) which is conveyed through conduit178, tube 176, conduit 173, tube 141, cavity 135 in valve segment 129,and vacuum slot 116 to evacuate the air from the vacuum valve chamber113 on the valve piston 196 which conditions the main control valve CVfor operation to control operative energization of the vacuum-motor VM.

Initial depression of the pedal P to its first dashed line position inFIGURE 1 simultaneously moves the valve sleeve and piston 105, 106respectively, power member PA, plunger 77 to the positions shown inFIGURE 7 wherein the master cylinder MC generates resistance to furthermovement of the above components as a unit effected by the initialoperator force on the pedal P transmitted to said parts by the valvespring 122 without modulating the preloaded status of the latter. Uponthe operator applying increased pressure to the pedal against saidresistance following such initial application thereof, the valve sleeveis displaced relatively to the valve piston 1116 from normal offposition, which relative displacement is accommodated by yielding of thevalve spring 122 induced by the resistance of the master cylinderfluiddisplacing parts reacting on the plunger 77. The said relativedisplacement being provided by the predeterminately spaced normaldisposition of the working face 143 on the valve housing VH with respectto the power member PA best demonstrated in FIGURE 2, it being recalledthat the forward extension 119 on the valve piston 106 projects throughthe opening 68 in the thrust plate 56 into abutting relation with theplate 48 forming part of the power assembly PA whereby the valve piston106 moves as a unit with the power asesmbly under infiuence of the valvespring 122 at all operating positions of the main control valve CV. Whenthis latter condition prevails, which corresponds to the relativedisposition aforesaid of the valve sleeve 1195 with respect to the powerassembly PA, the main and auxiliary control valves CV and AVrespectively may be said to be fully closed or off, that is to say, themotor chambers 45, 46 are interconnected and vented to atmosphere viasaid air filter device AF to establish equivalent pressures therein. Theaforesaid relative movement of the valve sleeve 1115 moves thecontrol-slot 111 into increasing exposure with respect to the vacuumvalve chamber 118 after first cutting off communication of this slotfrom the atmospheric valve chamber 121 thereby inducing evacuation ofair from the power chamber 45 via the tube 176, conduit 175 andconnected arcuate cavity in the upper half 128 of the valve housing VH,control-slot 111 and vacuum chamber 118.

During relative movement of the valve sleeve 105 to place the maincontrol valve CV in operating position, the spring seat member 5 movesconjointly with said sleeve due to the interconnecting pins 64, thusWithdrawing said spring seat member from the end of the poppet stem 2%to enable the poppet head 1% to engage the seat 196 under influence ofsome pressure differential and the normally preloaded leaf-spring 203.This seating operation of the poppet valve 197 establishes closedcondition of the auxiliary air valve AV and is so timed with the openingof the main control valve CV that the poppet valve becomes seated duringthe lapped position of the working land 1117 on the valve piston 106with respect to the control-slot 111 to enable the establishment ofnegative pressure in the power chamber 45 to thus produce differentialpressures in the chambers 45, 46 for power-activation of the boostermotor VM.

It is thus seen that closure of the air control valve AV is sosynchronized with the opening of the main control valve CV that thepower chamber 45 is placed under control of the latter valve duringpowenactivation of the booster motor VM, but upon release of operatorforce from the pedal I, the booster motor VM becomes inactivated as aconsequence of the valve elements 1535, 1% returning to their normal offpositions shown in FIG- URES 1 and 2 under influence of springs 102 and122. This normalizing of the main control valve CV enables the springseat member 95 to assume its normal disposition shown in FIGURES l and 2under influence of spring 102, and wherein this member engages thepoppet valve stem 2% and thus operates the same to unseat the poppethead and thereby interconnect the motor chambers 45, 46 via thepassageway 195, and the control-slot 111 in the sleeve 105 to restorebalanced pressure conditions within said chambers and thereby inactivatethe booster motor VM.

It is important to note here that the main control valve CV ischaracterized by a unitary construction completely independent of thepower assembly PA which it controls. This independent disposition beingprovided by novel slidable support of the valve unit on a portion of themotor casing, by utilizing that portion of the valve sleeve 195 exposedrearwardly of the valve housing VH, and which is acted on by the pedalP, thereby providing unison and relative sliding movements of the mainvalve elements 1%, 1416 to effect a sensitized follow-up action thereofin synchronisrn with the vacuum relief valve AV, and the ever presentreaction from spring 1592, and spring 122 as well, to oppose operationof the pedal P, contributes to a very smooth and efiicient operation ofthe control valve mechanism CV in accordance with the operator forceapplied to the pedal.

The manually adjustable element 123 against which the valve spring 122reacts, provides different preloaded settings of said spring so thatpedal force may be varied in accordance with the initial work-loadreacting thereagainst whereby a relatively soft or hard pedal isavailable during the initiatory thrust-transmitting operation, thuseliminating the necessity, and cost as well, of having to install a newset of spring conditions for each particular pedal feel as may bedesired by the driving public. Thus, for example, if spring 122 isinstalled under a preloaded weight of 204%, all that is required toobtain a harder pedal is to withdraw the nut 123 from the working land117 to the extent necessary to induce the desired pretension in saidspring. A shim washer of the proper thickness may be inserted betweenthe valve land 117 and adjusted position of the nut 123 to provide adefinite position of the nut for each setting thereof corresponding tothe preloaded weight at which the spring is desired to operate.

Mechanical Coupling etwcen the Power Member and Control Valve Piston andOperation Thereof Figures 8 and 9 This modification incorporates in thevacuum booster VM mechanical means for coupling the control valve piston106a to the power diaphragm plate 56a to move axially as a unit whileaccommodating limited relative radial displacement therebetween to avoidcritical and rigid coaxial relationship thereof. The structurecomprising this novel coupling means includes an integral reduceddiameter circular extension 345 which terminates in an annularoutstanding flange 346 at the inner end of 12 the extension 11% on thevalve piston 106a, to provide an annular space 347 therebetween. Theconfronting end of the opening 68a is closed by a wall 348 provided witha radially disposed opening or slot 349 therethrough slightly wider thanthe diameter of the extension 345 open at its inner end, and of a lengthslightly longer than the radius of the opening 68a. intersecting theperimeter of hole 68:: and the inner end of the slot 349 is a circularhole 359 through the plate 56a of slightly larger diameter than theflange 346, the intersecting points on the perimeter aforesaid mergingwith the circumference at the full diameter of the hole 354 to providean opening 351* t which places the marginal portions of the slot 349 inline with the space 347. The flange 346 is now ready to be radiallymoved into coaxial disposition with respect to the opening 68a whichoperation, when completed, disposses the forward end of the valve piston106a in engagement with the marginal portion of the slot 349 therebycoupling the main control valve CV and plate 56a to move axially as aunit.

It is thus seen that this novel coupling arrangement enables the valvepiston 10M and therefore the main control valve assembly CV to bedetachably connected to the power member PA thereby providing easyassembly and disassembly of the main control valve CV independently ofthe pressure-responsive unit PA. This coupling also insures exactness ofthe follow-up movement be tween the valve sleeve 1135a and piston 106aat all relative positions thereof in controlling the operation of thevacuum-motor VM since under no circumstances can the valve piston 196abecome axially separated from the power diaphragm thrust plate 56a.

The present invention contributes two principal novel combinations overthe prior art, and over the control valve mechanism disclosed in mycopending application Serial No. 684,946, earlier filed on September 19,1957, as follows:

1) The combination of the disclosed auxiliary control valve AV and themain control'valve CV; and

(2) The combination of the disclosed air control valve AV and the vacuumcontrol function only of the main control valve CV.

In the first combination, the air control valve AV serves as anauxiliary valve to the air control function of the main control valveCV; while, in the second combination, the air control function of themain control valve CV is eliminated by permanently isolating the controlslot 111 from the atmospheric valve chamber 121, thus placing fullcontrol of the induction of air into the power chamber 45 on theauxiliary control valve AV. The aforesaid isolation of the control-slot111 being effected by widening the working land 117 sufficiently tomaintain said slot covered when the sleeve and piston elements 105, 10hrespectively are disposed in normal off positions as shown in FIGURE 2.

Should the source of pressure fail or become inadequate, the operatorcan effect straight-through" assist or full operation of the plunger 77directly, by merely applying suflicient force on the pedal P to bringthe inner end of the valve housing VH and/or sleeve into engagement withthe confronting surface portion on the thrust plate 56. In thisdisposition of the main control valve CV, the full relative operatingmovement thereof has been taken up.

Moreover, it should be manifest that spring 102 continuously reacts onthe valve sleeve 105, but only on the power assembly PA in a releasingdirection thereby utilizing the full pressure differential force in thebooster 13 motor VM for operation of the plunger 77 rather than, as inprior art control valve mechanisms, dissipate some of the power force inovercoming the reaction from re turn spring that continuously reacts onthe power-piston or diaphragm as the case may be.

A further noteworthy feature in the present valve mechanism CV is theprovision of the usual operating relationship of the valve working land117 and control slot 111 wherein there is provided the off, lapped, andon positions of control, the lapped position being effective tostabilize the power assembly PA in any operating position by maintainingsubstantially a uniform force on the pedal P at such operating positionwhereby the valve mechanism may be held lapped with mini mum operatorforce to maintain the energized status of the booster motor VM at thegiven position of the pedal. In this conection, it should be pointed outthat when the main control valve CV is lapped as explained above, theauxiliary control valve AV is seated to isolate the two motor chambers45, 46 as is understood.

It is important to note that the reaction device RD serves the importantfunction of transmitting reaction from the master cylinder MC to thevalve sleeve 105, said reaction being induced by operation of the deviceto operating position under influence of initial operator force appliedto the pedal P prior to operative energization of the booster motor VM,to condition the master cylinder to pressurize the fluid therein andthereby provide resistance (work-load) to movement of the plunger 77reacting on the valve mechanism CV thus causing the spring 122 to yieldwith consequent relative movement of the valve sleeve 105 and springseat member 95 with respect to the valve piston 106 and poppet element197 respectively under increasing force on the pedal P by the operator.During such conditioning operation aforesaid, the spring 102progressively increases its tension on the spring seat member 95 andvalve sleeve 105 connected to the pedal P, to supplement the reactionfrom the master cylinder via the reaction device RD. The latter springserves the important function of continuous reaction on the valve sleeve105, and on the power assembly PA in a releasing direction only, in themanner previously described.

Accordingly, it is seen that initial operator force applied to the pedalP actually operates the reaction device RD and the master cylinderpiston to positions wherein these two components are conditioned toperform their respective functions upon the booster motor VM becomingenergized as a consequence of increasing force on the pedal P after suchinitial application thereof. Therefore, the present invention disclosesa definite and requisite cooperative relationship between the boostermotor VM and master cylinder MC actuated thereby for the motor to attainan operative status as well as the master cylinder. Neither of these twoprincipal components can carry out their respective functions untilinitial operator force has been applied to the pedal P to dispose thereaction device RD and the master cylinder in operating positionscorresponding substantially to FIGURE 5.

The simplicity and economy of the disclosed main control valve mechanismCV and its independent mounting, if desired, within the motor casingenable servicing without having to replace part or all of the associatedpower assembly PA controlled thereby, makes it most desirable as acontrol means for pressure differential operated motors utilized tooperate in part motor vehicle brakes and/ or steering apparatuscharacterized by a follow-up sequence of control between anoperator-operated member and a power-activated member, and wherein theoperator member is operable to automatically effect a straight-throughapplication of operator force on the device controlled in part by suchmotors.

Although the embodiments of my invention disclosed herein are wellcalculated to fulfill the objects stated, it will be understood that Ido not wish to be limited to the exact construction and/ or arrangementof parts shown, since it is evident that modifications, variations,changes and substitutions may be made therein without departing from theproper scope or fair meaning of the subjoined claims.

Having thus described my invention, I claim:

1. In a control valve mechanism adapted to control a power membermovable from normal position to perform work under influence of apressure differential, said mechanism having a pair of complementaryvalve elements, one of which is displaceable relatively to the other, asource of pressure diiferent from atmosphere communicating with one ofsaid valve elements, a fluid chamber between said valve elements incontinuous communication with said source, an atmospheric chambercoaxially disposed with respect to said fluid chamber between said valveelements, a working land on the other of said valve elements cooperatingwith a control port in the one valve element to selectively connect saidport to said fluid chamber and to said atmospheric chamber, a fluidconnection between said port and power member, a normally preloadedspring reacting between said valve elements to establish the same in arelative normal position, another normally preloaded spring reactingcontinuously on said one valve element only to assist the first namedspring in establishing the valve mechanism in said normal position incooperation with said first-named spring, means on the other valveelement in continuous follow-up engagement with the power member, asupport extension fixed with respect to said power member for slidablyreceiving a portion of said one valve element whereby both of said valveelements are operatively mounted as a unit inde* dependently of saidpower member, a pair of normally engaged abutment-engaging portions onsaid valve elements respectively to define their normal relativeposition, another pair of normally spaced abutment-engaging portions onsaid one valve element and power member respectively for defining therelative displacement of said valve elements out of normal position, anoperator-operated member adapted to act directly on said one valveelement to effect said relative displacement thereof in opposition tothe two springs aforesaid, the resistance provided by said work tomovement of said power member under initial operator-actuation thereofas a unit with said valve elements in said normal relative position as afunction of the thrust-transmitting capacity of the first-named springin normally preloaded status to oppose such unitary movement, producessaid relative displacement accommodated by yielding of said first-namedspring under additional operator-actuation of said one valve element,the improvement which comprises: an auxiliary air control valve havingan element displaceable from normally open position to closed positionin synchronism with said one valve element under influence of saidadditional operatoractuation to render said relative displacementcontrol by said complementary valve elements effective; and a thirdnormally preloaded spring operatively associated with said air controlvalve element for biasing the same toward its closed position.

2. A control valve mechanism constructed in accordance with claim 1including a threaded cylindrical extension projecting coaxially from oneend of the other valve element into the atmospheric chamber aforesaid;and a manually rotatable element threadedly engaging said extension intonormally engaged relation with the one end of said valve element forreceiving reaction from the firstnamed spring operably disposed withinsaid atmospheric chamber whereby the preloaded status of said spring maybe varied in accordance with the axially adjusted position of saidrotatable element.

3. In a control valve mechanism adapted to control a power membermovable from normal position to perform work under influence of apressure differential, said mechanism having an inner valve element andan outer valve element telescopically-related and relativelydisplaceable for controlling operation of said power member, a pair ofcoaxially disposed bores formed respectively in opposite ends of theouter valve element with one of said bores receiving the inner valveelement in airtight sea-led relation thereto, a thrust wall separatingthe inner ends of said coaxial bores, an atmospheric valve chamberdisposed between the thrust wall and confron ing end of the inner valveelement, an annular vacuum chamber disposed between said valve elementsin coaxial relationship with respect to said atmospheric chamber, afluid opening in the outer valve element interconnecting a pressuresource with said vacuum chamber, a port in the outer valve elementinterconnecting said atmospheric chamber with the atmosphere, afluid-control opening in the outer valve element normally communicatingwith the atmospheric chamber, a pair of cooperating abutment-engagingportions provided respectively on said power member and outer valveelement for defining relative displacement of said valve elements,another pair of cooperating abutment-engaging portions providedrespectively on said valve elements for defining the relative normalposition thereof, a normally preloaded spring operably disposed withinsaid atmospheric valve chamber to react between said thrust wall andconfronting end of the inner valve element to bias them apart to saidnormal relative position and accommodate their relative displacementtoward each other within the limits defined bysaid pair ofabutment-engaging portions on said outer valve element and power memberrespectively, an extension on said inner valve element in continuousengagement with said power member to provide unitary movement thereofunder influence of the first-named spring, another normally preloadedspring reacting. continuously on the outer valve element in cooperationwith said firstnamed spring to establish the normally released positionof said valve mechanism, tubular conduit means for in terconnecting. oneside of the outer valve element with said source of pressure, and theopposite side thereof to the power member aforesaid whereby relativedisplacement of one of the valve elements with respect to the other andto the power member is accommodated, a stationary member, anoperator-operated member adapted to act directly on the thrust wall inthe outer valve element to effect said relative displacement thereof,the

resistance provided by said work to movement of said power member as aunit with said valve elements effected as a function of the preloadedstatus of said firstnamed spring generated in response to initialoperatoractuation, induces said relative displacement of the outer valveelement upon additional operator-actuation of the latter, complementalmeans on the valve mechanism and said stationary member for slidablysupporting the former as a unit independently of the power member, the

improvement which comprises: an auxiliary air control valve having anelement displaceable from normally open position to closed position insynchronism with said outer valve element under influence ofoperator-actuation to establish difierential pressures on opposite sidesof said power member to activate the same; a third normally preloadedspring operatively associated with said air control element for biasingthe same toward its closed position; and mechanically interconnectingmeans between said outer valve element and the air control element toeffect synchronous movement of said two last-named elements.

4. A control valve mechanism constructed in accordance with claim 3wherein said tubular conduit means comprise: a flexible conduit havingone end communicating with the outer valve element and the other endconnected to the power member, and another flexible conduitinterconnecting the said one side of the outer valve element with saidsource of pressure.

5. A control valve mechanism constructed in accordance with claim 3wherein the said two openings in the outer valve element arelongitudinally spaced in diametrically disposed relationship through thewall thereof in continuous communication with axial bore in the innerend thereof, said openings cooperating with a pair of longitudinallyspaced annular lands on the inner valve element to define said annularvacuum chamber therebetween whereby said vacuum chamber is in continuouscommunication with said fluid opening connected to said source ofpressure, and one of said annular lands is adapted to selectivelycontrol communication of the fluidcontrol opening with said vacuumchamber and with said atmospheric chamber in response to relativedisplacement of the outer valve element with respect to the inner valveelement.

6. A control valve mechanism constructed in accordance with claim 5including a valve housing mounted on said outer valve element to producea unitary assembly, said valve housing comprising: a sleeve segmenttelescopically disposed on the outer valve element in airtight sealedrelationship therewith; a pair of diametrically disposed cavities in theinner cylindrical surface of said sleeve segment, one of said cavitieshaving continuous communication with the first-named opening in theouter valve element connected to said source of pressure, and the othercavity having continuous communication with the fluid-control opening insaid outer valve element; a pair of radially aligned oppositely disposedembossments integral with said sleeve segment; a passageway in each ofsaid embossments in communication respectively with each of saidcavities; another passageway in each of said embossments intersectingrespectively the first-named passageways whereby said first-namedopening and the fluid-control opening are connected to said source ofpressure and to the power member respectively.

7. A control valve mechanism constructed in accordance with claim 6wherein said sleeve segment comprises: two semicircular sections witheach' section incorporating one of said cavities and one of saidembossments; a pair of oppositely disposed flanges integral with each ofsaid sections, said two pairs of flanges having complemental confrontingsurfaces flush with the ends of the semicircular sections; a pair ofregistering holes through each pair of confronting flanges, one of saidpair of holes being threaded and the other unthreaded; and a cap screwprojecting through the unthreaded hole into threaded engagement with theregistering threaded hole in each pair of flanges to clamp both sectionsin airtight sealed relation on the outer valve element to produce aunitary assembly thereof.

8. In a control valve mechanism adapted to control a power membermovable from normal position to perform work under influence of apressure differential, said mechanism having an inner valve element andan outer valve element telescopically-related and relativelydisplaceable slidably supported as a unit independently of said powermember on a stationary member for controlling operation of said powermember, a pair of co axial bores formed respectively in the outer andinner ends of the outer valve element with the inner bore adapted toslidably receive the inner valve element in airtight sealed relation, athrust wall separating the inner confronting ends of said coaxial bores,an annular vacuum chamber disposed between said valve elements, a fluidopening in the outer valve element interconnecting a source of negativepressure with said vacuum chamber, an atmospheric valve chamber disposedbetween said thrust wall and confronting end of the inner valve element,a port in the outer valve element interconnecting said atmosphericchamber with the atmosphere, a fluid-control opening in the outer valveelement normally communicating with the atmospheric valve chamber, apair of cooperating abutment-engaging portions provided respectively onsaid valve elements for defining the relative normal position thereof;another pair of cooperating abutment-engaging portions providedrespectively on the outer valve element and said power member fordefining relative displacement of said valve elements, a normallypreloaded compression spring reacting between the inner valve elementand said thrust wall to establish the normal relative position of saidvalve elements, another normally preloaded compression springcontinuously reacting on the router valve element in cooperation withsaid first-named spring to establish the normal position of said valvemechanism, a mechanical connection between the movable power member andinner valve element adapted to connect them for axial movement as a unitin both directions, an inner annular working land on said inner valveelement defining one end of said annular vacuum chamber, for selectivelyconnecting the fluid control opening in the outer valve element toatmosphere and to said vacuum valve chamber to control operativeenergization of the power member, said working land being normallydisposed with substantially half of the fluid-control "openingcommunicating with the atmospheric valve chamber, an operator-operatedmember adapted to act directly on said thrust wall in the outer valveelement to displace the same relatively to said inner valve element as afunction of resistance generated by said work to oppose movement of saidpower member as a unit with said valve elements under influence ofinitial operator-actuation of the outer valve element transmittedthrough the first-named spring in pre-loaded status to the inner valveelement, the improvement which comprises: an auxiliary control valveoperatively mounted on the power member in radially offset dispositionwith respect to the axis thereof, said auxiliary valve having an elementmovable to open and closed positions with respect to a passagewaythrough said power member, whereby the air control of the valvemechanism is expedited in synchronism with movement of said outer valveelement; a third normally preloaded spring operatively associated withthe valve element of said auxiliary valve to bias the same to itsnormally open position when the valve mechanism is normalized; andanother me chanical connection between said outer valve element andelement of said auxiliary valve to effect said synchronous movementthereof under influence of operator-actuation of said outer valveelement in a normalizing direction.

9. In a control valve mechanism adapted to control the movable wall of afluid pressure-activated motor, a pair of cooperating valve elementsmovable relatively at a plurality of closely spaced stations definingthe full operating stroke of said wall to control movement of the latterin response to follow-up movement of an operator-operated member fromand toward a normal position thereof, a normally preloaded springreacting between said pair of valve elements to establish a normalrelative position thereof, a fixed member, another normally preloadedspring continuously reacting between said fixed member and one of saidpair of valve elements to bias the latter toward said normal position incooperation with said first-named spring, the improvement whichcomprises: a passageway through said wall normally open to balancepressures on opposite sides of said wall; an auxiliary control valveincluding an element spring-biased to a position closing said passagewayto isolate said op posite sides of said wall to enable differentialpressures to be effective thereon under control of relative movement ofsaid pair of valve elements from their normal position at each of theirstations aforesaid in response to operator member movement from itsnormal position; and a movable mechanical connection between said onevalve element and the spring-biased element of said auxiliary valveenabling unitary movement thereof against said spring bias relative tothe other of said pair of valve elements, to a different positionopening said passageway thus cooperating with said pair of valveelements to balance pressures on opposite sides of said wall uponrelative movement of said pair of valve elements effecting said normalposition thereof at each of their stations aforesaid in response tooperator member movement toward its normal position under jointinfluence of the two springs aforesaid.

10. In control valve mechanism adapted to control a power member movablefrom a normal position to perform work under influence of a pressuredifferential and an operator-operated member having follow-up movementfrom a normal position to control said power member, the improvementwhich comprises: a pair of cooperating telescopically-relatedspring-loaded elements coaxially disposed with respect to the axis ofsaid power member, said elements being adapted to render said pressuredifferential effective to move said power member p relative d pl m n frm th n rmal RQ ifi Q under operator-actuation of one of said elements; apassageway through said power member normally open to balance pressureson v opposite sides thereof, said passageway being offset radially fromthe ,axis ,of said power m a hi pr n -bia ed el m m vabl s iated withsaid passageway in synchronism with one of a pa .o e m n to norma p n da s wa a xe m m e a no ma y p e oad d sp aswat nl us reacting betweensaid fixed member and said one element of the pair of elements, incooperation with the spring load on the latter elements to establish thenormal position of all three valve elements wherein said pair ofelements cooperate with said third element moved against its spring biaswith respect to said passageway to open the same and thereby balancingpressures on opposite sides of said power member; and mechanical meansinterconnecting said one element of the said pair of elements with saidthird element to enable synchronous movement thereof relative to theother element of said pair of elements to augment the reaction from saidlast-mentioned spring in accordance with the effective operatingposition of said operator member from its normal position.

11. In a control valve mechanism adapted to control a power membermovable to perform work under influence of a pressure differential andan operator-operated member having normally released positionsrespectively, the improvement which comprises: a pair oftelescopicallyrelated cooperating elements coaxially disposed withrespect to the axis of said power member in operative follow-upassociation therewith to control the same, said elements beingrelatively displaceable from normal pressure balancing position withrespect to said power member, to operating position whereat pressuredifferential is effective on opposite sides of said power member to movethe same from normal position, in response to operator-actuation of oneof said pair of elements; a normally proloaded spring reacting betweensaid valve elements to establish the normal position thereof; apassageway through said power member normally open to cooperate with thepressure balancing position of said pair of elements, said passagewaybeing offset radially from the axis of said power member; a thirdspring-biased valve element movably associated with said passageway insynchronism with said one valve element, to normally open saidpassageway against said spring bias; a fixed member; another normallypreloaded spring continuously reacting on said fixed member and said onevalve element, to produce progressively increasing resistance tomovement of the latter element during relative displacement of said pairof valve elements in accordance with the effective operating position ofthe operator member from its normal position, said last-mentioned springopposing the spring bias on said third valve element and cooperatingwith said firstmentioned spring to establish the normal position of allthree valve elements to effect said pressure balance; and mechanicalmeans interconnecting said one valve element with said third valveelement to enable synchronous movement thereof relative to the other ofsaid pair of valve elements to augment said resistance from saidlast-mentioned spring.

12. In control valve mechanism adapted to control a fluidpressure-activated motor having a fluid chamber enclosure and a movablewall dividing said chamber into opposing fluid pressure chambers, and asource of pressure different from atmosphere, the improvement which 1%comprises: a pair of interfitting valve elements coaxial with said wall,and normally blocking communication between one of said opposed chambersand said source; a passageway through said wall adapted to normallyinterconnect said opposed chambers to balance pressures therein whensaid pair of elements is in blocking position; a third valve elementoperatively associated with said passageway to open and close the same,said last-named valve element being spring-biased to closed positionwherein said opposed chambers are isolated from each other insynchronism with said pair of valve elements relatively displaced tointerconnect said source with said one opposed chamber to establishdifferential pressures in said opposed chambers, and being operable toopen position against its spring bias in synchronism with said pair ofvalve elements operated to normal blocking position to balance pressuresin said opposed chambers; mechanical means interconnecting one of saidpair of valve elements with said third valve elements to move as a unitrelatively to the other of said pair of valve elements; a normallypreloaded spring reacting between said pair of valve elements to biasthem toward normal blocking position; another normally preloaded springcontinuously reacting on a portion of said chamber enclosure and saidone valve element, to produce progressively augmented resistance tomovement of the latter element during relative displacement of said pairof valve elements; and an operatoroperated member for effecting relativedisplacement of said pair of valve elements in opposition to said springbetween said pair of valve elements.

References Cited in the file of this patent UNITED STATES PATENTS2,152,084 Paine Mar. 28, 1939 2,331,238 Schnell Oct. 5, 1943 2,517,005MacDuff Aug. 1, 1950 2,972,339 Randol Feb. 21, 1961

1. IN A CONTROL VALVE MECHANISM ADAPTED TO CONTROL A POWER MEMBERMOVABLE FROM NORMAL POSITION TO PERFORM WORK UNDER INFLUENCE OF APRESSURE DIFFERENTIAL, SAID MECHANISM HAVING A PAIR OF COMPLEMENTARYVALVE ELEMENTS, ONE OF WHICH IS DISPLACEABLE RELATIVELY TO THE OTHER, ASOURCE OF PRESSURE DIFFERENT FROM ATMOSPHERE COMMUNICATING WITH ONE OFSAID VALVE ELEMENTS, A FLUID CHAMBER BETWEEN SAID VALVE ELEMENTS INCONTINUOUS COMMUNICATION WITH SAID SOURCE, AN ATMOSPHERIC CHAMBERCOAXIALLY DISPOSED WITH RESPECT TO SAID FLUID CHAMBER BETWEEN SAID VALVEELEMENTS, A WORKING LAND ON THE OTHER OF SAID VALVE ELEMENTS COOPERATINGWITH A CONTROL PORT IN THE ONE VALVE ELEMENT TO SELECTIVELY CONNECT SAIDPORT TO SAID FLUID CHAMBER AND TO SAID ATMOSPHERIC CHAMBER, A FLUIDCONNECTION BETWEEN SAID PORT AND POWER MEMBER, A NORMALLY PRELOADEDSPRING REACTING BETWEEN SAID VALVE ELEMENTS TO ESTABLISH THE SAME IN ARELATIVE NORMAL POSITION, ANOTHER NORMALLY PRELOADED SPRING REACTINGCONTINUOUSLY ON SAID ONE VALVE ELEMENT ONLY TO ASSIST THE FIRST NAMEDSPRING IN ESTABLISHING THE VALVE MECHANISM IN SAID NORMAL POSITION INCOOPERATION WITH SAID FIRST-NAMED SPRING, MEANS ON THE OTHER VALVEELEMENT IN CONTINUOUS FOLLOW-UP ENGAGEMENT WITH THE POWER MEMBER, ASUPPORT EXTENSION FIXED WITH RESPECT TO SAID POWER MEMBER FOR SLIDABLYRECEIVING A PORTION OF SAID ONE VALVE ELEMENT WHEREBY BOTH OF SAID VALVEELEMENTS ARE OPERATIVELY MOUNTED AS A UNIT INDEDEPENDENTLY OF SAID POWERMEMBER, A PAIR OF NORMALLY ENGAGED ABUTMENT-ENGAGING PORTIONS ON SAIDVALVE ELEMENTS RESPECTIVELY TO DEFINE THEIR NORMAL RELATIVE POSITION,AN-